"The Amazing Psych-Man & Tap-Man, Issue 2" is the fourth episode of season six. A local drug syndicate known as the Caminos falls under attack by a masked vigilante called The Mantis, and Lassiter is soured by this since The Mantis has already made more progress than the police. Shawn is also put off, due to Juliet expressing an admiration for The Mantis' efforts. Shawn and Gus believe that a new cop is the vigilante, but as they put the pieces together, they start to believe that the Mantis' efforts may not be altruistic.

A report on TV tells us that a regional drug trafficking gang, The Camino Drug Syndicate, has been successfully moving thousands of kilos of product through the streets of Santa Barbara.

Shawn and Gus are in hot pursuit of four criminals. Gus pulls a hammy and forces them to stop. When Gus finally recovers, they approach the criminals to see they have already been taken. Shawn approaches the now tied-up criminals and sees that the shadowy figure left a note in one of their mouths that simply says: "The Mantis". Later, SBPD arrives to get some answers. Just when they think they have no solid leads on who accosted the bad guys, they all look up and see a man, wearing a neoprene bodysuit, run and leap off the rear of the building. From this, Shawn and Gus are convinced this was the work of a real life super hero.

Back at SBPD, a reporter, Reginald Parker, from the Santa Barbara Sentinel is questioning Lassiter and Vick about the vigilante/super hero guy called The Mantis that took down the drug ring criminals. Lassiter is soured by this line of questioning because this vigilante has made more progress in taking down the drug ring than SBPD has.

Later, Juliet presents information regarding The Mantis's recent criminal takedowns. Shawn is visibly jealous of The Mantis, as Juliet appears to be impressed by his brave efforts.

Desperate to find out who The Mantis is, Shawn has a "vision" that clues in the SBPD that lead him to believe Camino's drug shipments are clocked by certain phases of the moon. Shawn then "psychically" relays this information to Juliet and Lassiter. They are willing to entertain Shawn's vision and decide to obtain a warrant to check out the docks.

They arrive at the docks and are shocked to see the bad guys have already been taken out by The Mantis. From this, Shawn concludes that there is no way that The Mantis could have known that the bad guys would be at this location, on the same night and time as Shawn "divined", unless The Mantis was someone on the inside... someone who works for the SBPD.

Back at the SBPD, Shawn and Gus seek out possible options for who could be The Mantis. They predict that he may be the new officer named Scott Reynolds just transferred to the SBPD — a man who is particularly fit.

Shawn "psychically envisions" a clue from a text on Juliet's phone regarding the Camino's next drug shipment. From this, Shawn is able to arrive on the scene before the SBPD does. However, this scenario backfires for Shawn when they rip the mask off the supposed real Mantis and discover that it's Shawn... in the Mantis's mask and outfit. Shawn tells the truth about what happened: The Mantis knocked Shawn out, dressed in his clothes, and fled.

Shawn shares his "inside job" theory to the group. Lassiter tells Shawn to prove it, and Shawn runs up to Officer Reynolds telling him that he should reveal his true identity — that he is The Mantis. However, after Shawn discovers that Reynold's has no marks on his
body that would indictate he was in a fight, this theory is quickly dismissed.

Later, Juliet shows Shawn a picture of the one the bad guys The Mantis knocked out. Next to him is a bag of drugs. Shawn Flashback's to the moment he saw this same guy on the ground and immediately remembers that there wasn't a bag of drugs next to the body, and puts it together that The Mantis was the one who planted the bag of drugs next to the criminal. From this, Shawn theorizes that The Mantis was creating this crime scene. But SBPD isn't quick to buy into Shawn's theory.

The Mantis sends Shawn the clothes he stole off Shawn's body when he took him down the other night.

Just then, Juliet gets a tip from The Mantis: to run DNA on the perp and therefore get led to an unsolved murder from last year. He also mentions Camino's next meeting time.

They arrive at the supposed Syndicate meeting location and see The Mantis standing over a dead body with blood on his hands. Mantis then flees the scene. They immediately think Mantis was the one who murdered him.

As much as Shawn dislikes this Mantis guy, he doesn't believe he's a murderer. Armed with this theory, Shawn remembers that the Mantis sent the clothes he stole from Shawn back to him from the cleaners. Inside the shirt, Shawn sees a tag that leads them to the Dry Cleaners that The Mantis used. There, they get a number that leads them to an address: the Mantis's apartment downtown.

At the apartment, they discover The Mantis's true identity... he is Reginald Parker — the reporter that was questioning Lassiter at the SBPD earlier. The Mantis explains his reasoning for vigilantism and that he was set-up for murder by the syndicate. Shawn and Gus believe him, as his story checks out. The Mantis says he is going to retire his Mantis character in light of this murder accusation.

However, Shawn convinces him that there is still time to catch the bad guys and absolve Mantis's tarnished name. But Mantis says he could never fully take down the syndicate because he had no idea how the drugs were actually getting to the syndicate. Right then, Shawn fkashbacks to an open cargo container containing panes of glass he saw at the docks. From this, Shawn makes the determination that the syndicate had been moving their product by melting it down and mixing it in glass. Armed with this new theory, The Mantis suits back up and is able to convince Gus and Shawn to suit up with him, as "super hero decoys" and to go catch the bad guys. Shawn wears a baseball catcher's outfit, and Gus is dressed as his "Tap Man" super hero character from childhood.

At the warehouse, the three "super heroes" — The Mantis, The Catch & Tap Man — work fast to try to take down the syndicate. The Mantis is able to take down a bunch of the bad guys before the SWAT team arrives and is able to take care of the rest. However, in the midst of all of this, The Mantis somehow gets away undetected, leaving Shawn, Gus, and the rest of the SBPD confused as to why he would flee.

Later, Shawn stops by Mantis's apartment but is shocked to see that the entire place has been cleared out, and The Mantis is nowhere to be found. Just then, Shawn realizes something — that The Mantis's goal wasn't to take down the syndicate, but rather to steal the syndicate's millions of dollars in drug money once he had taken them out. Shawn realizes what he must do: suit up as The Catch again and try to find Mantis in the midst of fleeing the city.

The Catch and The Mantis face off. Shawn isn't doing too great against Mantis, and Mantis escapes. Just then, Juliet and Lassiter show up as back up. After a chase, Shawn "The Catch" Spencer takes down The Mantis once and for all. And with that, The Mantis is finally arrested, and the Camino Drug Syndicate case is laid to rest at last.

When confronted by Juliet after Shawn is outted as not being Mantis, Shawn says some of the lyrics to the theme song, I Know, You Know, by The Friendly Indians. He says "I know, you know, I wasn't telling the truth, I know you know..."